package com.wc.AlgoOJ_train.train5_数据结构.c4_二叉树.DS0302_遍历一般二叉树;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

/**
 * @Author congege
 * @Description
 * @Date Created in 2024/2/4-12:51
 * http://43.138.190.70:8888/p/DS0302
 */
public class Main {
    static FastReader sc = new FastReader();
    static PrintWriter out = new PrintWriter(System.out);
    static int N = 1050;
    static int[][] t = new int[N][2];
    static int n;

    public static void main(String[] args) {
        n = sc.nextInt();
        for (int i = 1; i <= n; i++) {
            t[i][0] = sc.nextInt();
            t[i][1] = sc.nextInt();
        }
        dfsQ(1);
        out.println();
        dfsZ(1);
        out.println();
        dfsL(1);
        out.println();
        out.flush();
    }

    static void dfsQ(int root) {
        if (root == 0) {
            return;
        }
        out.print(root + " ");
        dfsQ(t[root][0]);
        dfsQ(t[root][1]);
    }

    static void dfsZ(int root) {
        if (root == 0) {
            return;
        }
        dfsZ(t[root][0]);
        out.print(root +" ");
        dfsZ(t[root][1]);
    }

    static void dfsL(int root) {
        if (root == 0) {
            return;
        }
        dfsL(t[root][0]);
        dfsL(t[root][1]);
        out.print(root + " ");
    }
}

class FastReader {
    StringTokenizer st;
    BufferedReader br;

    FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

    String nextLine() {
        String s = "";
        try {
            s = br.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return s;
    }

    long nextLong() {
        return Long.parseLong(next());
    }

    double nextDouble() {
        return Double.parseDouble(next());
    }

    // 是否由下一个
    boolean hasNext() {
        while (st == null || !st.hasMoreTokens()) {
            try {
                String line = br.readLine();
                if (line == null)
                    return false;
                st = new StringTokenizer(line);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return true;
    }
}
